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11.
According to the present research situation of conductive polymer materials- polyaniline (PAN) ,we reviewed the structure and properties of PAN, the effecting factors and the best conditions of electrochemical synthesis and chemical synthesis of PAN , the doping mechanism of PAN, inorganic and organic acid doping,secondary doping, the method of increase soublity and processability of PAN and the broad application of PAN. The development derection and prospect of PAN are pointed out. 相似文献
12.
在进行水文预报时,由于影响河道洪水的因素众多,常用的水文预报模型往往不符合实际水文系统的客观规律。对这类系统的参数辨识要求算法具有较强的实时跟踪能力,以适应模拟或预测洪水运动变化过程的要求。利用洪水预报误差信息,对BP网络洪水实时预报校正模型与方法进行了探讨,提出了两种实时预报方法。第一:运用最小二乘递推算法,引入时变遗忘因子实时跟踪模型中时变参数的变化,建立了神经网络在非线性系统中动态的系统输入、输出数据之间的映射关系。第二:利用BP网络模型对误差的可识别性,将模型对输出变量的预报误差再次作为输出变量,对网络可能预报的误差进行实时修正。计算实例表明:以上两种方法提高了神经网络在水文领域的预报精度,给BP神经网络的实时预报方法提供了新的途径。 相似文献
13.
费县扬水站经过多年建设,存在机电设备老化、配套不合理以及效率低下等问题,通过改进水泵、改变转速、改变叶片安装角以及改进管路装置,提高了泵站效率,降低了运行成本,收到较好的效果。 相似文献
14.
变铅青链霉菌的DNA上存在着一种异常的修饰,使其在含有微量Fe~(++)的缓冲液中电泳时,双链DNA遭到降解。DNA的切割是位点特异性的。与已知修饰特征的DNA进行同步试验发现,变铅青链霉菌的这种特异性修饰与目前所发现的修饰系统(如DNA甲基化)均不相同,很可能是一种新的修饰系统。 相似文献
15.
针对纸制军事地图矢量化问题进行研究,提出一种基于自适应遗传算法的军事地形图矢量化方法,并在生成新的个体后,增加个体修正操作,提高个体的适应度。在该算法中,提出一种即考虑进化代数对算法的影响,又考虑到每代不同个体适应度作用的自适应交叉概率和变异概率。通过与传统方法的实验比较,证明该方法的可用性和有效性。 相似文献
16.
方竹属(Chimonobambusa)四方竹(C.quadrangularis (Fenzi) Makino)是优良的笋竹两用乡土经济竹种。根据对四方竹生物、生态特性观察,在复层林分的下层及山谷荫湿环境纯林生长发育良好。总结了四方竹野生竹林垦复改造技术,以分类经营为原则,通过劈山清杂、松土垦复、水肥管理,建立集约经营、一般丰产经营与生态经营竹林。集约与一般丰产经营竹林单位面积立竹量提高了290.1%,平均胸径提高了177.9%,2008年竹林单位面积平均出笋23 067个(采挖与留笋养竹总和),已基本建成正常生产经营竹林。 相似文献
17.
Yasuhiro Inoue Takayuki Matsuura Tatsuji Ohara Koji Azegami 《Journal of General Plant Pathology》2006,72(2):111-118
The entire genome of bacteriophage OP1, lytic for Xanthomonas oryzae pv. oryzae causing bacterial leaf blight of rice, and the partial genomes of related phages were sequenced and analyzed. The OP1 genome comprises double-stranded, 4785-bp long DNA with 51.1% G + C content. Fifty-nine open reading frames (ORFs) were detected.
ORF25 had similarity with the tail fiber gene of phages, whose product is related to host specificity. The ORF25 regions were
amplified from four host-range mutants (OP1h, OP1hC, OP1h2, and OP1h2C) by polymerase chain reaction, and their deduced amino acid sequences were compared. Three mutants (OP1hC, OP1h2, OP1h2C) had duplications of a small domain in the N-terminal portion, although there were slight differences in the position of the duplicated sequences. One mutant OP1h had substituted amino acids in the duplication region. New mutants isolated in the laboratory (OP1hC and OP1h2C from OP1 and OP1h2) acquired the ability to lyse strain N5874 belonging to phagovar (lysotype) C. However, they rapidly lost this lytic ability
when incubated with other phagovars. This loss was always accompanied by a loss of the characteristic repeats, suggesting
that the host range of OP1-related phages changed mainly through duplication and deletion of a small domain in ORF25.
The nucleotide sequence data reported are available in the DDBJ/EMBL/GenBank databases under the accession numbers AP008979,
AB214312 to AB214316 相似文献
18.
Skeletal muscle is the most abundant tissue and the main component of muscle in animals.The process of skeletal muscle cell's proliferation and differentiation is the basis of muscle development and it's directly affects the meat production performance of domestic animals.It has been found that epigenetic modification plays an important role in regulating the proliferation and differentiation of skeletal muscle cells.In this study,the effects of epigenetics on skeletal muscle in terms of the effects of DNA methylation on the proliferation and differentiation of skeletal muscle cells,the selection and expression of factors regulated by histone acetylation,the regulation of non-coding RNA,and the effects of chromosome remodeling.Research progress in the process of muscle cell proliferation and differentiation,briefly describes the effects of different modification methods and factors on the two processes of skeletal muscle proliferation and differentiation.At the same time,the methods and means used by predecessor in the study of skeletal muscle proliferation and differentiation were reviewed,and then the role of apparent regulatory factors in skeletal muscle growth was analyzed.The purpose was to further explain the important role of epigenetic modification in the proliferation and differentiation of skeletal muscle,enhanced the understanding of the regulation of skeletal muscle proliferation and differentiation,provided a reference path for integration with animal production,and also provided skeletal muscle.Molecular regulation of such as growth and development provided more reference materials. 相似文献
19.
20.
人参总皂苷及其衍生物对小鼠淋巴细胞和NK细胞免疫活性的影响 总被引:6,自引:0,他引:6
为了提高人参总皂苷的生物学活性,对其进行了硫酸化修饰,并探讨总皂苷及其衍生物对小鼠脾T、B淋巴细胞增殖(MTT法)和NK细胞杀伤活性(乳酸脱氢酶释放法)的影响。结果表明,2种衍生物质量浓度在50~500 mg/L时可以促进小鼠脾T、B淋巴细胞的分化增殖和NK细胞对YAC-1的杀伤作用,质量浓度较高时促进作用明显优于总皂苷;衍生物质量浓度达到1 400 mg/L时,仍然可以显著促进T淋巴细胞的增殖。试验结果提示,人参皂苷的这种衍生物有可能成为一种毒副作用较小、免疫活性更强的药物。 相似文献